Abstract: The stress state on a 2 000 m³ liquid gas sphere after it has operated one year is onalyzed. The residual stress and working stress was measured on the spot by x-ray method and PSF-2M x-ray stress gauge produced by Rigaku . The results show that though the sphere was once heat treated globally as it was packed, there still existed as high as 0.90 σ_s after operation one year. Therefore, local heat treatment was adopted so that the total residual stress decreased (only individual point is high).